Shock absorber



' Patented Jan. 3; :1928.l l UNITED' STATES: 'PATENT OFFIf-IE.`

JOHN A. STEVENS, OE LWELL, MASSACHUSETTS, ASSIGNOR T STEVENS PBODUUISCO., OF LOWELL, MASSACHUSETTS, A CORPORATION 0F DELAWARE.

sHocx Ansonnnn Application inea August' 1s, 192s. seriai'm. 50,022.

This invention relates to an improvement to mounted between adjacentends of the in shock absorbers for use in conjunction spring liand thechassis 2.

withand supplementing the usual body The shock absorbing device 3comprises a springs of a vehicle. Y body portion 4 having a projectingarm 5 5 The outstanding defect .infknown shock carrying a spindle 6which pivotally receives 60 absorbers prior 4to this invention has b eenthe end of the frame or chassis 2 so thatl their inability to overcomethe undulatlng freedom of movementis permitted between` movementcharacteristic of an automobile sald chassis and device; lThe upper endof when traveling at the higherl rates of speed. 'thebody portion 4receives a hollow spherical Even the best highways 'ontainripples oncasing 7 forming-a compression chamber 7 65 their surface that cause anautomobile to 'rigidly held inV place on said lbody portion sway andoscillate transmitting to the ocby a series of screws 8. A pneumaticfabriccupants ofthe vehicle a rising and falling 'casing 9 containing an'inner rubbercasing movement that isa source of great annoyance 10 1smounted within the hollow 'sphericaland oftentimes a cause of illness.Present member 7 and is adapted to be inflated 70 day shock absorbersthat are sufficiently rethrough a valve 11 extending through theupsponsive and resilient to neutralize shocks do per portion of saidspherical member 7, outer -not react to .quickly arrest the relativemove- Casing/9 and inner casing 10. The valve 1l Ament between thechassisand springs of the may be of the type commonly -employed for 2 0vehicle but on the contrary'actually augment miiatmg pneumatic casings.The pneumatic 75 l maintained;- and to provide ai devieefso ed on top oft theundulating tendency of the vehicle. `casing may ,be inflatedftocontain a1r at va Objects of this invention are provide 1n pressuredepending on the weight of tg a .shock absorber readily -responsive'. toall ve cle so as to make the shock absorbing shocks and able tocounteract and neutralizel de vice suiiiciently responsive to counteractthem eiectively and at the same time adaptand neutralize all shocksreceived by the ve- 80 ed to bring the forces acting on jthe s ringshicle. andchassis of the vehicle into e uili rium A plunger 12 threadedon the reduced without aiectingthe resiliency of t e s rings three andability of the device to neutralize s ocks; gages the underside of thecasing -9 and ur- 3o to provide a. dash-pot in a'shock absorbing thercompresses the air within said com res- 85 device so that the normalvposition .of the sionchamber on an upward movement t ere-- chassis ofthe vehicle relative to the spi'in of, An annular washerl having anopenand wheels under a normal load is ez'ective y ing 16 receivin theplunger rod 14 is mountel body portion 4 Within the simple in'itsconstruction that it canbe easily lower end of the spherical casing 7andA S 40 claims appended thereto.

applied to'an *automobileVV or. other vehicle adapted t0 Center theplunger l2 and rod 14 without changing an parts'.V f vrelatively to Athecasing 9. Other objects of t e invention will be a A tubular s leeve 16having an exterior anparent from the detailed description and tt; nularprojectmn forming a shoulder 17 is in threaded engagement with the lower95 For purposes of illustration the device is threaded end oft e plungerrod-14. A relashown in the 'accompanying drawings in tively largecoilspring 19 surrounds the which plunger rod 14 and sleeve 16 and ismounted AFig. 1 is a side elevationof the device atwe'en. the shoulder17 and the washer 1 5, f 4 5 lacied Vtizi the chassis and springs of ave- Within thelarge coil spring 19 is a smaller 100 c e; an Y Fig.. 2 isa vertical sectional view' of the the sleeve 16 and. device at'rightangles to the view shown in VSlgiig 20 functions only Fig. 1. 19 hasbeen suiiiciently compressed to com- Y As illustrated the numeral -1Ydesignates the press the smaller spring 20 between the 105 usualsemi-ellipticfleaffspring attached to shoulder.18 on which it-is seated.and the the axle of a vehicle while the-numeral 2 Washer 1 '5- Y 'ndesignates the chassis or frame carried by The lower end of the sleeve16 projects said spring. Ashock absorbing device desigdownwardly fromthe lower end of the i5 n ated as a whole bythe numeral is adaptedplunger rod' 1 4 and is pivotally received in 110 lugs 21 integral withan arm 22 intermediate the end of said arm. One end of said arm 22 ispivotally attached to the body portion 4 while the opposite end of saidarm pivotally receives the projecting end of the spring 1 so that reemovement between the 'leaf spring 1, arm 22 and body portion 4 ispermitted.

A dash-pot designated as a whole by the reierence numeral 23 is pivotedto the arm 22 immediately below the point where the sleeve 16 is pivotedto said arm. The dashpot 23 comprises a cylinder 24 having a lower cover25 secured thereto through the medium of the bolts 26. The cover 25 hasa depending lug 27 which receives a spindle 28 pivotally attached to thearm 22. The upper end of the cylinder 24 has an upstanding externallythreaded tubular projection 29 which acts as a bearing for the pistonrod 30 carryin aL piston 31 on its lower end. An interna ly tainingpacking 33 is ni screw-threaded engagement with the bearing 29 andserves to prevent any loss of compression in the cylinder -between thepiston rod andbearing. An upstanding arm 34 is rigidly attached at oneend to a ,side of the body portion 4 while its other end is in the formof an eye 35 receiving the projecting end of a member 36 having lugs 37which receive the upper end of the piston rod 30. A bolt 38 having a nut39 projects through the lugs 37 and piston rod 3() to secure saidmembers together. Suitable oiling grooves 40 are provided in the bolt 38and spindle 28 as shown in Fig. 2.

The p'ston 31 has a narrow opening 41 extendin therethrough between itscenter and its perl heral edge and a one way valve 42 spaced om theopening 41. When the piston 31 moves downwardly relatively to the 24 thevalve will raise when the pressure of the iuid below the pistonbestantially comes suici'ent and thus allow the pressure above and belowthe piston to become subequal but when the piston moves upwardlyrelatively to the cylinder the valve will always remain in closedposition.

The operation of the device is as follows: When a shock is transmittedto the spring 1 the force of said shock is not directly carried to theframe 2 but causes the plunger 12 to rise upwardly against the pressureof the compressed air in the compression chamber 7 so that the shock iscounteracted and neutralized and very slightly conveyed to the occupantsof the vehicle as is well known and understood. The dash-pot 23 not onlyserves to impede and soften the shock transmitted to the frame 2 butwhen the forces acting on the vehicle are such as to tend to cause theplunger 14 to continually oscillate in the chamber 7 and thus give anundulating movement to the frame y by reason of threaded retainmg nut 32con-v 2 that tendency will be quickly arrested -the dash-pot acting as adrag on the movement of the plunger and thus causing a balancing of theforces acting on the plunger land establishing complete equilibrium.lVhen the vehicle receives a shook it is transmitted to the springs,chassis and shock absorbing element with the result that the saidsprings and chassis initially tend to approach each other while theplunger 12 moves upwardly in the compression chamber 7 causing thecylinder 24 to move upwardly relatively to the piston 31. The upwardmovement-of the cylinder 24 relatively to the piston 31 compresses theair in the cylinder portion below the piston until the pressure thereinis sufcient to lift the valve 42 allowing the pressure on both sides ofthe piston to become substantially equal and arresting the brakingeffect of the piston so that the resiliency of the shock absorbingelements is maintained. The reaction of the shock absorbing elements 3and 23 to the initial movement just described will cause the piston 31to move upwardly relatively 24 and the plunger 12 to move downwardly,due to the mounting o the elements, with the valve 42 remaining closedthroughout the entire upward stroke of the piston. The air above thepiston 31 will be gradually compressed exercising increasing pressure onthe piston so that the maximum braking elect of the. device 24 isproduced on this movement. The opening 41 permits some reduction in thepressure on the piston so that the piston will not be suddenly arrestedand thus impair the device in eeetivel counteracting and neutralizingshocks. he size and number of openings suchas 41 is ad- )usted asnecessary to prevent the sudden Varrest of the piston. The valve 42 maybe reversed if the predominant retardation is desired on the down strokeof the piston and if the same retardation is desired in both directionsthe valve may be omitted and the opening or .openings through the pistonmade. of such size as to ive the desired retardation. However, un ermost conditions of use superior results are obtained with the valvearranged as shown.

It frequently happens that after the force of a severe shock has set themovable elements of the shock absorbing device 3 in motion the rippleson the surface of the highway will furnish suicient impetus to saidmovable. elementsto sustain them in their initial movements with theresult that the body of the vehicle assumes the rapid undulatingmovement previously described. The dash-pot 23 not only serves to checkthe rapid oscillating tendency which normally follows' a shock but. alsoovercomes the undulating movement of the vehicle by reason of theintensified force of its drag on the to the cylinder i d evice 3 whichgradually increases in intensity on the upward movement of the' piston31 of the dash-pot.

The application of the' device here shownand described is not restrictedto automobiles or other vehicles but the device may be 'cie form of thedevice here shown used wherever there are two parts movable relativelyto each other by a sudden movement which, itiis desired to cushion. I doclaims.

V dampening I claim 1. -Ashock absorber adapted to be mounted on avehicle comprising pneumatic means for neutralizing and counteractingthe shocks received'by saidvehicle, and a dashpot for assisting thepneumatic means in neutralizing the shock and providing a action towardmotion in either quickly arresting the forces set' in motion by saidshock to bring them into a state of equilibrium.

2. A 'shock absorber adapted to be mounted between the frame and springsof a Vvehicle comprising a compression chamber containing a.compressible fluid, a plunger adapted to oscillate in said'chamber, andmeans acting as a drag on the plungercas regards motion in eitherdirection but exercising its maximum retarding influence on movement oftheparts in which the springs and frame of the vehicle move away fromeach other quickly to arrest the relative movementof said plunger andchamber.

3. A shock absorber adapted to be mounted between the frame and springsof a vehicle comprising a compression chamber containing a compressiblefluid, a plunger adapted to oscilalte in said chamber, themovement ofsaid plunger acting as a. drag as regards vrelative movement o theplunger direction ior and chamber in 'either direction, the drag havingits maximum retarding influence ont movement of .said plunger by whichthe springs and frame of the vehicle move away from each other quicklyto arrest the relative movement of'said plunger and chamber.

4:. A shock absorber for a vehicle, comprisingV a compression chamber, a4plunger rod having a head adapted tooscillatem said chamber, va.-relatively large coil sprm sur'- rounding the plunger rod and adapte tobe f compressed on the upward movement of the head, a relatively smallcoil spring surrounding the plunger and contained within the large coilspring, and means acting as a. drag Aon said head and exercising itsmaximum retarding effect on the down stroke thereof quickly to arrestthe relative movement of said head in said chamber.

5. A shock absorber adapted to be mounted on the usual frame andspringsof a-vefilled cylinder anda hicle comprising a compressionchamber containing pressed air mounted on the frame of said vehicle, alunger carried by the springs of said vehic e adapted to oscillate insaid chamber and bea-r on said vessel, a piston lrigidly attached tosaid compression chamger oper- .hicle comprising a body portion having acompression chamber containing compressed air mounted on the frame of'said vehicle, a plunger carried by the springs of said vehicle adaptedto oscillate in said chamber, a piston having a piston rod attached tothe body portion of said compression chamber, a cylinder attached tosaid plunger receiving said piston, a one way' valve in said pistonadapted to lift on the down'stroke of said piston.

7. A shock absorber adapted to be mounted between the frame and springsof-a vehicle comprising means for neutralizing and counteracting theshocks received by said vehicle, and means for assisting said irst namedmeans and for bringing said irst named means into a state ofequilibrium, said second named means comprising an air piston workintherein, bleedl openings in the pistonl hea and a lcheck valve in one ofsaid bleed openings so placed that little resistance is ifered to theinitial shock but a greater resistance is oiered to the recoil therefromand to successive shocks.

8. A shock absorber vfor a vehicle, comprising a pneumatic'-L means anda spring means for neutralizing theshocks and means for dampening theoscillationsof said first but offering its maximum resistance to motionin the opposite direction therefrom.

10. A shock absorber for a vehicle, comprising a pneumatic means and aspring means for neutralizing the shocks, and means of dampening theoscillations of said first named means including a cylinder filled witha compressible .Huid and a piston )peraiging 3 therein -having bleedopenings in its hea a check valve on at least one of the openings in thepiston head allowing flow upwardlv only, whereby the movement ofthepistohv a collapsible vessel filled with comby an initial shock in adownward direction tends to assist the pneumatic and spring means, andan upward movement, accompanied by the closing of the check valve slowsup the recoil and provides for a quick return to the normal position ofall the parts.

. 11. An apparatus for absorbing the shocks caused by the relativemovement of two members comprising a compressible chamber adapted to betixed to one of said members, a plunger rod carried by the other` ofsaid members and having a head adapted to oscllate in said chamber, arelatively large coil spring surrounding the plunger rod and adapted tobe compressed on the upward movement of the head, a relatively smallcoil spring surrounding the plunger rod and contained within the largecoil spring, and means acting as a drag on said head and exercising itsmaximum retarding eiect on the down stroke thereof quickly to arrest.

the relative movement of said head in said chamber.

12. An apparatus for absorbing the shocks caused by the relativelmovement oftwo members comprising a body portion having a compressionchamber containing a compressible fluid which body portion is mountedonone of said members, a plunger carried by the other of said members andadapted to oscillate in said chamber, a piston having a rod attached tothe body portion ot said compression chamber, a cylinder attached tosaid plunger receiving said piston, a one way valve in said pistonadapted to lift on the down stroke of said piston.

Signed by me at Lowell, Massachusetts, this twelfth day of August, 1925.

JOHN A. STEVENS.

